Local Area Network Protocol Standards Information Technology Essay

Local area network referred to a network that works inside a building such as office, company and home office. LAN are used in small geographical area. LAN is capable in transferring data in a very fast speed that can up to 10Mbps in limited network distance. There are two types of network architecture that can be implemented in the local area network, peer-to-peer networking and client-server networking. The common types of connections that used in LAN are Ethernet and Token Ring.

LAN Standards and Protocols

Each network has its own rules and standards. Therefore, protocols are use in network technology to govern the communication between network and network. There are many different kinds of protocols, the most common protocol used in the OSI data link layer in LAN are Ethernet and Token Ring.

Ethernet

Ethernet is the most well-known type of local area network that most widely installed in offices, home offices and companies. The standard of an Ethernet is IEEE 802.3. Ethernet normally are used coaxial cable and sometimes different grades of twisted-pair cable as the transmission medium.

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Token Ring

Token Ring is a network that connects computers in a star or ring topology. It is originally developed by IBM Company. There will have a token ring that passed through the network to allow computers to access the network. The standard for Token Ring network is IEEE 802.5. A token bit will move around the ring from computer to another computer. If the computer wants to transmit a data, the data will attach to the token and pass to the next computer. It has to keep passing through computers in the network until it comes to the destination. If the computer doesn’t want to transmit any data, the token ring will just pass to the next computer.

Ethernet

Token Ring

Advantages

Cost Effective

Flexible to use in star and bus topologies

Simplicity of installation

Scalable, support upgrade

Allow packets to take turns to transmit, avoid collision.

Disadvantages

System will down during the heavy traffic in the network.

Needs proper network planning before installed.

Difficult to install.

Not cost effective.

Justification

After comparing both Ethernet and Token Ring, I had chosen Ethernet as the LAN protocol for the network. The very main reason of using Ethernet is because of its availability and popularity in today’s network system.

Secondly, it is simple to install and its scalability support upgrades in future. This is very important for the company as the company is still developing and probably will be adding more workers in the future.

Thirdly, the speed of Ethernet is fast and can support transfer speed from 1Mbps up to 100Mbps.

Wide Area Network (WAN)

Wide area network referred to a network that connecting multiples of LAN network together in a wide range. The distance range of a WAN can be between country and country. A very good example of WAN is the Internet.

WAN are connected using a router. A router can help to choose the most suitable path for a connection to reach to the destination. WAN are categorised into two main ways which is circuit switching and packet switching.

Circuit Switching

Circuit Switching is a connection will be establish between 2 network nodes before they can start transmitting data.

The bandwidth is only dedicated for the particular connection.

The connection will be terminated after the data transmission ends.

Examples for circuit switching are the telephone networks.

Packet Switching

In packet switching, data is broken up into packets before transmitted to the destination.

There is a destination address and sequencing information in every packet.

When reaching at destination node, the packets need to be reassembled.

Justification

Leased lines will be used in the proposed network. Leased lines normally are used in private networks. Advantages of using a leased line is because it is dedicated for private use only, people from other network will not have the chance to access the leased line. The disadvantage of using leased lines is it is very expensive compare to other WAN standards. Therefore, the transferring speed when connect each office in WAN is very fast and reliable. Leased lines connection is available 24 hours every day. Therefore, it is very suitable to

Internet Connection

In order of to connect the users to the Internet in the network, we need to have an internet connection to access the Internet. In here, I choose Symmetric Digital Subscriber Line (SDSL) for the company.

SDSL provides the equal bandwidth for downstream and upstream for the connection. This is very suitable for business companies because they have big usage on uploading information to the Internet and also download information from the Internet.

Here, we used T1 line which is 1.54Mbps with the SDSL for the internet connection of the company. SDSL will require a modem in order to connect to the Internet. The modem will be provided by the local service provider.

Networks Architecture

Peer to peer networking

Peer to peer networking is defined as “a type of network in which each workstation has equivalent capabilities and responsibilities” (About.com, 2010).

Small Scale

Peer to peer networking is a network architecture which designed for small scale business that can support 10-15 numbers of users. Therefore, if the company is having a plan to upgrade the network in the future, peer to peer networking definitely is not suitable for the company.

Resource Sharing

Secondly, peer to peer networking doesn’t have the ability of sharing files, printers, projectors and etc. Therefore, if the company uses peer to peer networking, they probably have issues on resources sharing.

Data Redundancy

Thirdly, as in terms of peer, means there is no centralized server for the network, each computer works as individual. As a result, it is difficult for user to retrieve data and synchronize data as the data are stored separately at different computers.

Advantages

Disadvantages

No dedicated administrator.

No security on the network

No dedicated server required. 

No centralization on network

Each workstation has individual resources. 

Limited numbers of user.

Cost effective

Too many passwords to remember

Client-server networking

Client-server describes a type of computer application architecture within network computing that designates tasks between clients that instigate requests and servers that process requests. (E-How.com, 2010)

Centralization

In client-server networking, information are stored in a centralized server and allows ten computers or above to access them and share information throughout the network. Centralization also makes the finding of resources easier as all the resources are stored in a centralized server.

Scalability

Scalability is also one of the important fact in client-server network. Using this architecture, the network is able to scale to a certain numbers of users and also can expand in the future if needed.

Security

Thirdly, security is no more an issue in client-server networking because only qualified user with valid login username and password can access to the system.

Advantages

Disadvantages

Scalability – can support upgrade.

Not cost effective due to the high price of server.

Higher efficiency and optimization.

Dependability on server. If any point of the server fails, the system will be facing failure.

Centralised network, resources, users are control through the server.

Need to maintain by high skill technician, hence higher maintenance fees.

Flexibility, new technology can be integrated into the network easily.

Will be suffering from congestion during heavy traffic.

Justification

After comparing both peer-to-peer networking and client-server networking, the architecture that would best suits the company is client-server networking. Considering the company is still growing and probably having expansion of networking in the future, the number of staffs in the company in the range of 35-40 users, the scalability, flexibility, centralization and security characteristic of client-server network are the best choice.

Topology

Star Topology

The star topology is the most common network topology that most home and office are using. Computer and other devices in star topology are connected to the center and attached on a small device called the central hub. The central hub plays the role of a switch to control the flow from the source machine to the destination machine. The central can either be a hub, router or switch.

Mesh Topology

Every computer and device in this topology will have a dedicated link to each device. They are connected using point-to-point. If a network has n device, then the network will have n (n-1)/2 link connected to each device.

Bus Topology

Bus topology is a network that connects all computers in a single backbone. The backbone functions as a sharing platform where all devices in the network can use the backbone to transfer data.

Ring Topology

In ring topology, computers and devices are connected with the device on the both side of it and forms a ring shape. A signal will be passed along the ring shape in only one direction from one to another till it reaches its destination. The device in the ring topology incorporates with a repeater to regenerate the signal and passed them through the network.

Topology

Cable Media

Advantages

Disadvantages

Star

Twisted Pair

Fiber Optic

Easy to install because of its simplicity.

Easy to install, replace or remove computers or other devices during expansion

When one node fails, it won’t affect the other nodes.

Fully dependent on the central hub, when the hub fails the whole network will fail.

Need a lot of cabling to connect many computers.

Mesh

Twisted Pair

Coaxial

Has dedicated link to each computer

Easy to identify the fault node.

Lack of centralization.

Data redundancy at each computer.

Bus

Twisted Pair

Coaxial

Fiber Optic

Less cabling

Low cost

Easy to extend

System will slow down during heavy network traffic

If the back bone failed, it will affect the whole system

Ring

Twisted Pair

Easy in installing or reconfiguring

If one node fails, the whole network will be affected

Difficult to add new nodes to the network.

Difficulty in troubleshooting.

Justification

In this assignment, we were asked to determine a suitable topology that the ICT Resources Malaysia Public Limited Company will be need within the office. Therefore, after doing a lot of researches in network topologies, we finally decided to choose star bus hybrid topology as the company’s topology.

Hybrid topology

Hybrid topologies basically is a topology which combines two type or more than two types of basic topology and inherits their advantages and make it more powerful and usable compare to using only one type of topology.

Advantages

Disadvantages

Hybrid topology are customize designed to meet the requirement of the network.

Nodes in the network can be expanded and removed easily.

Combines the simplicity and fault tolerance from bus and star topologies.

Can find out the failed node when a node is not working and carried out diagnostic test without affect the other part of the network.

Some specific device in hybrid topology might not suitable to use in other network topology and they become not reusable.

Transmission Medium

Transmission media allows a connection between sender and receiver. Transmission medium are categorized into two main categories which is guided media and unguided media.

Twisted pair cable

Twisted pair cable is a type of wire that twists together in pairs. The reason why the cable is being twisted together is to decrease the electromagnetic interference and noise that affect the data transmission along the cable. Twisted pair cable has two different categories, Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP).

Coaxial Cable

Coaxial cable is a type of cable that contains a copper conductor in the center. It also has a metal foil layer and braid which both is covered by an outer conductor. The metal foil layer helps to block interference that will affect the cable. The coaxial cable carries a higher frequency signal compares to twisted pair cables. Coaxial cables are categorized by the radio government rating which called the RG numbers.

Fiber Optic Cable

Fiber optic cables have glass conductors in its center. Fiber optic cables use light to transmit data instead of using electricity signal. It uses reflection to guide light travels along the channel. Fiber optic has two propagation mode, single mode and multi-mode. Multi-mode has two forms which are step index and graded index.

Twisted Pair

Coaxial

Fibre Optic

Frequency

100Hz-5MHz

100Khz-500MHz

–

Bandwidth

4mbps – 100mbps

10Mbps- 600Mbps

Up to 2Gbps

Advantages

Reduce noise and cross talks

Cost effective

Readily available

Flexible

Lighter weight compare to other media.

Easy to install

Higher bandwidth

Less vulnerable to interference than twisted pair

Resistance to noise

Less signal attenuation

Higher Bandwidth

Disadvantages

Vulnerable to signal distortion.

Low bandwidth.

Expensive to purchase

Bulky compared to twisted pair.

Very expensive.

Difficulty in installation or maintenance

Need skillful technician for maintenance.

Fragility- Glass fiber inside the cable are easily broken

Justification

UTP and Fibre Optic Cable are chosen for this network. The fibre optic cable will use as the back bone for the Ethernet and the UTP will be used as connecting the machines and devices in the network.

The reason fiber optic cables are used as the back bone in Ethernet because it has a very high bandwidth. In bus topology, the bandwidth of the backbone will decrease during heavy traffic; therefore if using fiber optic cables, the bandwidth will increase and won’t decrease easily. Fiber optic cable is highly security and not affect by electromagnetic interference.

For the UTP, its weight is lighter compare to STP because it doesn’t have the outer shield. Secondly, it is cost effective than using coaxial cable. Besides that, UTP has high availability in the market. When the cables are broken, replacement cable can be purchased from the market easily.

Servers

File Server

File server is a central storage of a network. It provides access control for user to access files, folder in a same network. User can share files and information without physically transfer using USB drive or portable hard disk.

FTP Server

File transfer protocol server is one of the oldest of the Internet service. It provides security and transfer control in transferring files.

Web Server

Provide web access and web storage to the users on the network.

Application Server

Application server acts as a middleware of the back-end application of the network and the front-end user. It allows users access the applications which stored in the database.

Print Server

Print server allows users in a network to share printers. User can use any printer in the network to print files instead of connecting every computer with a printer. This will reduce the cost to buy printers.

Database Server

Database server is a server that stores database for a company in a server. Database servers do job such as analyzing data, data storage, data manipulation and etc.

Email Server

Email server responsible in receiving emails from the network and send out the email to the receivers in another network. Email servers use SMTP (Simple Main Transfer Protocol) and POP3 (Post Office Protocol) when sending and receiving email.

Protocols

There are 5 protocols that I choose to apply in the network:

HTTP

Hypertext transfer protocol (HTTP) is a protocol that used in accessing data in the Internet. It transfers information such as image, hypertext, audio, video and etc. It used the service of TCP to transfer information. HTTP is used in the application layer of the OSI model.

DHCP

Dynamic host control protocol is a protocol that will auto assigning dynamic IP address to the machines on the network. When a computer connects to the network, it will send a request to the DHCP Server and ask for IP assigning. Then the server will send an offer to the machine then the machine will accept the IP. The machine is then connected to the network.

IP

Internet Protocol is the most common protocol that used in the Internet. It is used in the network layer in the OSI model. Its job is to send data from one computer to another. Data are broken into packet and every packet contains a header and its own information.

TCP

TCP is a protocol that allows two hosts to make a connection and transferring data. It also guarantees the transfer of data packets and make sure they arrived at destination in the same order like they were sent out. It is in the transport layer of the OSI model.

ICMP

Internet Control Message Protocol (ICMP) is a protocol that used to test the response of destination.

LAN Diagram

WAN Diagram

Floor Plan

Ground Floor

The departments that located in the ground floor are the Human Resource Department and the Sales and Marketing Department. The human resource department has 4 workers whereas the sales and marketing department has 6 workers. There are two printers in this floor.

First floor

First Floor

The CEO and secretary room is located at the 1st floor. The server room of the network also located at the 1st floor. There are two other departments in this floor which are Operation Department and Financial Department. Each of the departments has six workers. There are two printers in this floor.

Second Floor

At the second floor, there are customer service department and IT department. Customer service department has 3 workers and IT Department has 6 workers.

Limitation

Security

Although the network has a firewall to prevent network attack from hackers, it is still not good enough to fully blocking hackers from attacking the network. Therefore, the security of the network s

Performance

Performance of this network will be affected by the switches in the star topology. If the switches failed, the department will be affected. The performance of the network also will be affected by the backbone of the bus.

Gantt chart